Camshaft adjusting devices are generally used in valve train assemblies of internal combustion engines to vary the valve opening and closing times, whereby the consumption values of the internal combustion engine and the operating behavior in general may be improved.
One specific embodiment of the camshaft adjusting device, which has been proven and tested in practice, includes a vane adjuster having a stator and a rotor, which delimit an annular space, which is divided into multiple working chambers by projections and vanes. A pressure medium may be optionally applied to the working chambers, which is supplied to the working chambers on one side of the vanes of the rotor from a pressure medium reservoir in a pressure medium circuit via a pressure medium pump, and which is fed back into the pressure medium reservoir from the working chambers on the particular other side of the vanes. The control of the pressure medium flow, and thus the adjusting movement of the camshaft adjusting device, takes place, e.g., with the aid of a central valve having a complex structure of flow-through openings and control edges, and a valve body, which is movable within the central valve and which closes or unblocks the flow-through openings as a function of its position. The valve body itself is spring-loaded with respect to the central valve and is displaced against the spring force with the aid of an adjacent piston of an actuator for adjusting the rotation angle of the rotor with respect to the stator. The rotor is generally connected to the camshaft, while the stator is driven by a crankshaft of the internal combustion engine, e.g., via a chain or a belt, so that the rotation angle of the camshaft with respect to the crankshaft is also adjusted by the adjustment of the rotor with respect to the stator.
In principle, the camshaft must be supported, which may take place via a rolling bearing, e.g., for the purpose of minimizing friction. A camshaft adjusting device of this type, which includes a rolling bearing, is known, e.g., from DE 10 2010 005 603 A1 or WO 2010/020507 A1. In these specific embodiments, the axial overall length and, in particular, the distance between the vane adjuster and the bearing, is significantly determined by the supply of the pressure medium via radial through-flow channels and annular channels in the camshaft, so that these specific embodiments may be implemented only if a certain installation space is available. Moreover, increased bearing forces and flexural torques in the camshaft result due to the distance between the vane adjuster and the bearing.